introduction to biostatistics Flashcards
it is a branch of statistics that applies statical methods to a wide range of topics in science (examples)
biostatistics
(biology, medicine, public health)
it is a a fundamental discipline at the core of modern health and underpins most key public health research disciplines such as epidemiology and the services research
biostatistics
the study of factors that determine the occurrence and distribution of a disease in a population (example)
epidemiology
(prevalent disease in Palawan is malaria
- how many ppl hv immunity against malaria
- how many cases of malaria r there?)
briefly explain the 2 types of epidemiology
classical epidem: (population)
studies the distribution and determinates (how) of disease in a population
fr ex: study how many gets the flu each year and how
clinical epidem: (improve care for INDIV patients)
application of principles of epidemiology to clinical med
- patient care
- clinical decision making
= helps doc make btr decision abt diagnosing n treating
define
subject:
population:
subject: is anyone/ anything that is the focal point of the study and it is the source of data for the research
population: [totality of the grp] grp of indiv/ items which consists of all possible subjects of interest
true or false:
defining the subject/ population is one of the most critical step in research
true
the complete set group of individuals, whether that group comprises a nation or a group of people with common characteristics
population
what type of questionnaire do you give to the population rather than a sample?
census - answer of the whole population
a representative subset of population
sample
a process used in which a predetermined number of observations are taken from a larger population
sampling
it is a smaller set (or a subset) of the population
sample
it is a subset that provides an accurate picture of the whole population
Representative sample
explain why the data collection from a sampler may not be 1:1 to the data collected from the population but is very similar to one another
For example:
40 students in the class.
Sir asked whether they wanted asynch or synch. Most said asynch.
Now if Sir gets a sample of 15 students. Majority will still say asynch. Hence, it is not 1:1 but very similar to each other.
if only certain members of the population are chosen systematically, this can be misinterpreted
how to avoid that
biased sample
to avoid that, use random sampling to ensure lack of bias
what are the strategies for obtaining a random sample
3 pri types:
simple random sampling
stratified random sampling
systematic random sampling
each type of random sample requires a list of the population
known as the sampling frame
sampling frame (example)
a list of subject from the population which is often assigned a unique number
(class list, student id, taste testing of pastries)
the strategies for choosing a random sample depends on…
the research question
how feasible it is to implement the randomization
A subset of a statistical population in which each member of the subset has an equal probability of being chosen and is meant to be an unbiased representation of a group.
simple random sample
simple random sample
advantage:
disadvantage:
advantage: each subject in the popu has the same chance of being selected
disadvantage: while representative of the popu, may not be reflective of the true popu - difficult to conduct in large sample sizes (Philippines)
how do you conduct simple random sampling
through a number generator
each subj is assigned a unique number (identifier) - then it is being drawn/ generated randomly
a method of sampling that involves the division of a population into smaller sub-groups known as strata
stratified random sample
stratified - cluster
stratified random sample
advantages:
disadvantages:
advantages: more representative of the population due to stratification - less biased
disadvantages: often involves more work in the beginning of the process of segmenting into strata
(CMLS students into their respective years)
how do you conduct stratified random sampling
popu are divided into several strata based on overarching traits (location, economic status)
total sample for the study will be representative of the popu as long as the no of subject s r sampled in each strata is proportional to the overall popu size
a method for selecting a sample from a population in a randomize manner as to minimize sampling error
systematic random sample
systematic random sample
advantage:
disadvantage:
advantage: easy to conduct once sampling frame is ordered and interval no. is selected
disadvantage: prone to bias
- sampling frame is unarranged
- similar characteristics for every 5th subject
how do you conduct systematic random sampling
interval no. is selected and will be the basis for the every subject from the popu
random starting point will also e selected which starts the chain of intervals
briefly explain the types of variables
categorical: limited to a known certain set of values
count variables: positive, whole numbers
continuous variables: “no natural gaps” - variables that measured instead of counted
briefly explain the types of categorical values
“categorical variables that…”
ordinal - different levles/ ordered no matter what
(stages of cancer, birt order, life cycle )
nominal - can be associated to a category but order does not matter
(taste, color, breeds)
dichotomous -only hv 2 lvls
(yes/ no options and gender)
which types of variable are discrete and which is not
discrete- categorical and count
not discrete - continuous
discrete: can have in-between values
Variables whose potential measures are limited to a known certain set of values. Because only a limited set of values are possible, categorical variables are known as discrete variables.
categorical variables
what are the 3 subtypes of Categorical Variables
ordinal
nominal
dichotomous
Variables that can take on positive, whole numbers and thus are considered discrete values. In between numbers do not count.
count variables
Variables that have only numerical values and have no “natural gaps” between numbers. These are
variables that are measured instead of counted and are best analyzed by multiplying , dividing, adding or subtracting the values.
continuous variables
categorical variables is aka
discrete variables
